SCHRÉDER - LUX LIVE 2016

HIGH TEMPERATURE LUMINAIRES

TREVOR LEIGHTON – REGIONAL TECHNICAL OFFICER IMEA

GCC: BEST PLACE FOR LED?

• -20°C

• 1 year warranty?

• L20 B90?

CRITICAL LED ISSUES IN GCC?

High Temperature Ta = 35-50°C

Light output

Lifetime

TRANSPORT LIGHTING IN EUROPE

NO LIGHT (!)

TRANSPORT LIGHTING IN GCC

HUGE ROADS

PUSHING THE CURRENT TECHNOLOGY TO THE EDGE

2 lanes, then 4 lanes

4 lanes, then 6…

14m pole height, then 20m

2cd/m2…

HOW CAN WE MANAGE THIS?

1500 mA + (!)

CHIP TECHNOLOGY – POWER DENSITY

1 mm2

350-500mA

2 mm2

350-700mA

4 mm2

700-1400mA

HOW DOES A CLIENT KNOW WHAT A “GOOD” FITTING FOR GCC IS?

QUALIFY YOUR REQUIREMENTS FIRST

CRI (colour rendering index) shall be >80?

Industry standard = >65

QUALIFY REQUIREMENTS

3 Steps Macadam's Ellipse?

Industry standard = 5

QUALIFY REQUIREMENTS

M class selection?

SZR = 6 – 2.5 = M3 = 1 cd/m2

BOQ?

• Wattage - 1,000 pcs x 200W LED?

• Lumen Package – 1,000 pcs x 14 klm?

• Design validation!

WHICH TEMPERATURE?

• 25? 35? 50? 55?

• Ta / Tq / Tj / Ts

• Highest daytime temperature?

• Average nighttime temperature?

EFFECT OF TEMPERATURE ON LED LUMINAIRES

The 3 types of temperature:

• Thermal Safety

• Ambient temperature factor

• Lifetime lumen losses

THERMAL SAFETY

Can the luminaire operate safely at 50°C or 55°C?

1. Driver – Tc / thermal cutout / ramp down

2. LED – Chip life 100,000 hours -> 99,950 hours?

3. Lens – Soften or melt = no photometry!

Thermal test report to include critical areas!

IEC 60598 / 62722 / UL 1598 / LM-84 flawed

SILICON LENSES?

Higher tolerance to heat = higher drive current

THERMAL SAFETY

Must make assumptionsabout 50°C Ta operation!

• Centre of luminaire

• Centre of PCBs

• Driver Tc

• Thermal camera?

• Take manufacturers advice

AMBIENT TEMPERATURE FACTOR

Luminaire

Ambient

Temperature

Factor LM-82

• LED Module, NOT luminaire

• Photometric test• Initial temperature x°C• Increase initial by 25°C• Increase by an additional amount

LM-82(Module NOT luminaire)

Ts – Solder point

Initial temp 25°C

Initial + 25°C (50°C)

One other temp:

(Schréder) 85°C

LM-82

ADQCC / Trustmark

DMA Spec

LUMEN DEPRECIATION OVER TIME AT TEMPERATURE (LLD)

50°C or 55°C Ambient for 50,000 hours? (Ta)

35°C = Realistic conditions for GCC (Tq)

1. Thermal Test – we need to know the Ts (solder point)

2. LM-80 – Data from Manufacturer (α & β)

3. TM-21 – Formula to calculate Lxx @ t

THERMAL TEST

1. Hottest Ts (solder point) @ 25°C Ta

2. Add difference for Tq (e.g. 35°C = + 10°C)

3. Go to LM-80 to find Alpha and Beta

LM-80

Take most appropriate α & β(E.G. DMA Spec.)

(3rd Party?!)

TM-21

LLD = β e^ (-αt)

t = 50,000 hours (DMA)

LLD = β e^ (-αt)Driving current

mASolder point

Temp. α α β Time hrs. (-αt) e^(-αt) LLD(%)

35055 7.52606 0.0000001 7.526E-07 0.979558 50000 -0.0376303 0.963068922 94.34%

85 7.52606 0.0000001 7.526E-07 0.979558 50000 -0.0376303 0.963068922 94.34%

500

55 7.52606 0.0000001 7.526E-07 0.979558 50000 -0.0376303 0.963068922 94.34%

85 7.52606 0.0000001 7.526E-07 0.979558 50000 -0.0376303 0.963068922 94.34%

105 7.52606 0.0000001 7.526E-07 0.979558 50000 -0.0376303 0.963068922 94.34%

700

55 1.07498 0.000001 1.075E-06 0.971213 50000 -0.053749 0.947669942 92.04%

85 1.07498 0.000001 1.075E-06 0.971213 50000 -0.053749 0.947669942 92.04%

105 1.07498 0.000001 1.075E-06 0.971213 50000 -0.053749 0.947669942 92.04%

100085 1.66797 0.000001 1.668E-06 0.978485 50000 -0.0833985 0.91998446 90.02%

105 3.9224 0.000001 3.922E-06 0.990859 50000 -0.19612 0.821913599 81.44%

(3rd Party test TM-21 certificate)

CRITICAL POINTS

• Thermal safety at daytime / max operating temperature

• Ensure LATF is not significant (LM-82 as a check)

• Make sure LLD is proven and applied to MF

MF = LLD x LDD

MF is not 0.7 for every case!

STANDARDS FOR LIFETIME

Component

LM-84 TM-26 / TM-28System

LM-80 TM-21

LM-84-14

Approved method for measuring lumen and colour maintenance for LED• Lamps

• Light Engines

• Luminaires

Main points of document

• Testing according to LM-79

• Rack for continuous burning, “interval testing”

• L50 and L70 mentioned – Not for Roadway luminaires

• Thermal Camera to detect hottest parts of PCB

• LM-80 is 6-10K hrs, LM-84 6K hrs = 2 years behind?

• No LED driver Tc mentioned

• Not realistic operating conditions – No glass? No lenses?

• Not practical nor sytemise-able for LED luminaire manufacturers !

THERMAL CAMERA - LM-84-14

STILL NOT PUBLISHED

TM-26

• LM-80 + TM-21 make no assumptions about catastrophic failure probability

• LM-80 uses very small sample size (e.g. 20-25 pieces)

• Driver to be considered

• Early / Spontaneous / Wear-out

• Projection model to assess confidence levels

TM-28-14

• Two methods: “Direct” and “Combined”

• 6,000 hours benchmark

• LM-79 periodically

• Sample set:

Direct = 3 luminaires

Combined = 5 luminaires

• 5 luminaires can extrapolate 1.5 x testing time (e.g. 6,000 x 1.5 = 9,000 hours)

• 50,000 hours? 6 x testing time maximum

• 15 luminaires tested for 8,333 hours!

• Third party? 30-40K USD minimum

• Product life cycle?

Not useful for high performance roadway luminaires!

KEY TAKEAWAYS

• Emphasis on System, not Components Luminaire Lumens per Circuit Watt at Temp and Time

Acurately delivered lumens per AED…

• LM-79 is good for 25 Deg C

• LM-82 is “reasonable” for increased temp

• Thermal testing needs to be logical and maybe regional

• MF needs to be adapted for LED and region

• Initial lumens into design is EVERYTHING

• LM-84/TM-28 for retrofit LED lamps only